Oil pressure generated in a mechanical oil pump driven by the engine is supplied to a v-belt continuously variable transmission. Pulley pressures (including a primary pulley pressure and a secondary pulley pressure) generated by using the oil pressure as a source pressure are supplied to a primary pulley and a secondary pulley. These pulley pressures are used to hold a belt and these pulley pressures are controlled to change a groove width in each of the pulleys in order to realize a shift.
In vehicles on which such a continuously variable transmission is mounted, a so-called coast stop control has been carried out to stop the engine not only when a vehicle is standing still but also before a vehicle comes to a halt for the purpose of improving fuel performance.
However, in the coast stop control, driving a mechanical oil pump is discontinued in accordance with suspension of the engine and it becomes difficult to ensure a sufficient pulley pressure for use in holding a belt with the likelihood of causing a belt to slip.
As a measure taken against such belt slippage, JP2011-007326A describes a technique for shifting a speed ratio of a continuously variable transmission to a predetermined slippage suppressing speed ratio before suspension of the engine.